The present invention relates to a power steering apparatus which is usable in a vehicle, for instance, an automobile and the like, and adapted to assist a steering torque to be inputted by a vehicle operator by using a rotational torque of an electric motor.
Japanese Patent Application Unexamined Publication No. 2009-46060 discloses an electric power steering apparatus including an electric motor which is driven to rotate in accordance with a steering input torque detected by a torque sensor provided on a steering input shaft. The rotational torque of the electric motor is transmitted to a steering output shaft through a worm reduction mechanism, to thereby assist a steering effort of a vehicle operator.
The electric power steering apparatus of the conventional art includes a joint for connecting a motor output shaft of the electric motor and a worm shaft. The joint is constituted of an external-teeth member to be press-fitted to the motor output shaft of the electric motor and an internal-teeth member to be press-fitted to the worm shaft. A damping member is interposed between the external-teeth member and the internal-teeth member to thereby suppress generation of noise due to vibration of the motor output shaft of the electric motor and the worm shaft.